Problem-Solving and Data AnalysisVery hardProbability that at least one of two independent events occurs
Problem-Solving and Data Analysis practice question
Two independent events have probabilities 0.3 and 0.5. What is the probability that at least one of the two events occurs?
Answer: 0.65 or 13/20
P(neither) = 0.7 × 0.5 = 0.35, so P(at least one) = 0.65.
Common wrong answers
- If you answered 0.8
- 0.8 adds the probabilities, counting both-occur twice.
- If you answered 0.15
- 0.15 is the probability that both occur.
- If you answered 0.35
- 0.35 is the probability that neither occurs.
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